Passerine birds are one of the few species other than humans that learn the sounds used for vocal communication during development. Vocal behavior is controlled by a highly localized system of interconnected brain nuclei, and both brain and behavior are sensitive to the influence of gonadal hormones. Thus, passerine birds provide a model system for studies of the neural and hormonal substrates of learned vocal behavior. Experiments are proposed to study the characteristics of vocal learning in two species, canaries (Serinus canarius) and zebra finches (Poephila guttata). Comparisons of these two species are interesting because zebra finches learn their vocalizations only during a restricted period of development, whereas canaries are able to learn new vocal patterns even in adulthood. Some of the approaches to be used rely on behavioral and neuroanatomical techniques, which have been successfully applied to this system by many investigators, including ourselves. A major emphasis of the current proposal is to apply electrophysiological techniques along with behavioral and morphological measures of vocal learning. A Research Career Development Award would enable me to make the necessary commitment to learning electrophysiological techniques, including the ability to make intracellular recordings both in vivo and in slice preparations. Such expertise would permit my lab to perform studies that combine behavioral, morphological and neurophysiological approaches, which would greatly enhance our understanding of neural mechanisms of vocal learning.